The Blood of the Walsungs(1965)

The siblings Sieglinde and Siegmund von Arnstatt are inseparable. Their arrogant manner is particularly felt by Sieglinde's fiancé, Lieutenant Justus von Beckerath. Siegmund jealously watches over his sister, with whom he falls into a frenzy of emotion during a performance of Richard Wagner's opera "Die Walküre." Beckerath realizes that he will never be able to break into the incestuous intimacy of the twins. Finally, Siegmund and Sieglinde give themselves over completely to their sensual intoxication...